#include <iostream>
#include <math.h>

using namespace std;

float C_to_F(float x);
void getUserInputs(float& value, float min, float max, string type);
float calculate(float mph, float degrees);

//m is min; M is max
//Fahrenheit Constants
const float Fm = -80;
const float FM = 121;
//Celcius Constants
const float Cm = -62;
const float CM = 49.5;
//Wind Speed Constants
const float Wm = 0;
const float WM = 231;

/*
Function: C_to_F
Input: Celcius(float)
Return: Fahrenheit(float)
Purpose: Converts celius to fahrenheit
*/
float C_to_F(float x)
{
    x *= 1.8;
    x += 32;
    return x;
}

/*
Function: GetUserInputs
Input: variable(float), min value(float) max value(float), variable's type(string)
Return: None
Purpose: Ask user for the value of type between min and max
*/
void getUserInputs(float& value, float min, float max, string type)
{
    while (value <= min - 1 || value >= max + 1)
    {
        cout << "What is the value of " << type << "?" << endl;
        cout << "(Enter a value between " << min << " & " << max << ")" << endl;
        cin >> value;
    }
}

/*
Function: calculate
Input: MPH(float), degrees F(float)
Return: Wind Chill(float)
Purpose: To calculate wind chill from wind speed and temperature
*/
float calculate(float mph, float degrees)
{
    return (35.74 + (0.6215 * degrees) - (35.75 * pow(mph, 0.16)) + (0.4275 * degrees * pow(mph, 0.16)));
}

/*
Function: main()
Input:None
Return:None
Purpose: Ask user what degree they will enter temp in and run functions based off that
*/
int main()
{
    char CorF = '0';
    float temp = 999999;
    float wSpeed = 999999;
    float windChill = 0;

    while (CorF != 'C' && CorF != 'F')
    {
        cout << "Do you want to enter in Fahrenheit (F) or Celsius (C)" << endl;
        cin >> CorF;
    }
    if (CorF == 'F')
    {
        getUserInputs(temp, Fm, FM, "Fahrenheit");
    }
    else
    {
        getUserInputs(temp, Cm, CM, "Celcius");
        temp = C_to_F(temp);
        cout << "That is " << temp << " degrees in Fahrenheit" << endl;
    }

    getUserInputs(wSpeed, Wm, WM, "Wind Speed");

    windChill = calculate(wSpeed, temp);

    cout << "At " << temp << " degrees Fahrenheit and at a wind speed of " << wSpeed << "MPH, the windchill is " << windChill << ".";
}